Method of producing artificial fibers



May 16, 1939. A. FORMHALS 2,158,415

METHOD OF PRODUCING A RTIFTCIATI FTBFRS Filed July 28, 195? 2Sheets-Sheet 1 IN VEX TOR.

A TTORNEYS.

May 16, 1939. A. FORMHALS 2,158,415

I METHOD OF PRODUCING ARTIFJCIAL FIBERS Filed July 28, 1937 2Sheets-Sheet 2 INVENTOR A TTOR;\'EYS.

Patented May 16, 1939 ETE SATES METHOD OF PRODUCING ARTIFICIAL FIBERSAnton Formhals, Mainz, Germany, assignor of forty-five one-hundredths toRichard Schrei-. ber-Gastell, Mainz, Germany Application July 28, 1937,Serial No. 156,168

2 Claims.

The present invention relates to the production of artificial fibers,and more particularly it relates to a process for the production ofartificial fibers by passing a stream of spinning solution containing avolatile solvent into a zone of electrical influence between twooppositely charged conductors or electrodes whereby to whip the saidstream of solution or cause the same to be rapidly traversed between theelectrodes. This whipping 9 or rapid traversing of the stream ofspinning solution during the evaporation of the solvent therefrom causesthe same to be drawn out into very fine fibers.

It is therefore an object of the present invention to provide a methodfor spinning of artificial fibers which comprises drawing a continuousstream of spinning solution into fine fibers by passing the same betweenelectrodes bearing high potential electric charges of opposite polarity.

It is another object of this invention to provide a method for theproduction of artificial fibers by permitting a continuously flowingstream of spinning solution to become partially set, and drawing thepartially set stream into fine fibers by passing the same betweenelectrodes bearing high potential electrical charges of oppositepolarity.

It is another object of the invention to produce by electrical means anartificial fiber having a decided curl 'or crimpl Other objects of theinvention will appear hereinafter.

In order to illustrate and describe the principles of the presentinvention, reference is made to the accompanying description to be takenin connection with the accompanying illustration, in which:

Figure l is a diagrammatic perspective view illustrating one form of theapplicants invention.

Figure 2 is a diagrammatic elevational view showing a second form of theapplicants invention.

Figure 3 is a perspective view illustrating a still further form of theinvention.

Figure 4 is a perspective view of still another modified form of theinvention,

Referring to Figure 1 of the drawings, -reference numeral ll designatesa container for a supply of spinning solution. Connected to the supplycontainer l I is a conduit l3 provided with a plurality of spinningnozzles I5, I6, I! and I8. The spinning solution is passed through theconduit l3 and spinning nozzles l5, I6, I! and I8 and permited to flowdownwardly between the electrically charged wire l9 and 20. The wires I9and 20 bear high potential charges of opposite polarity due to theirconnection with opposite poles for supplying high potential electricitydesignated by numeral 22. 'Means for producing high potential charges ofelectricity are well known in the art and it is therefore not necessaryto specifically describe or illustrate the same. The conductor wires l9and 20 may be charged with an alternating high potential current or witha constant direct or fluctuating direct current -w having a voltage offrom 25,000 to 100,000 volts.

The wires l9 and 20 are preferably stretched between stationaryinsulated supporting means 24 and 26. Each of the Wires, l9 and 20, willbe surrounded by an electrical field, and as the-l5 streams of spinningsolutipns from the nozzles flow downwardly between the wires I9 and 20,they will come within the electrical influence of the field surroundingone of the said wires which will cause the same to be attracted thereto.As the streams of spinning solutions approach one of the wires, forexample, the wire which is posiively charged, they will become chargedwith a positive charge and will then be repelled by the positivelycharged wire and will then be attracted by the negatively charged wire.As soon as the stream of spinning solution approaches the negativelycharged wire, the stream of solution will become charged negatively andwill then again be whipped or traversed towards the positively chargedwire. This rapid traversing or whipping of the stream .of spinningsolution back and forth between the negatively and positively chargedwires will cause the stream to be drawn out to very fine filaments whichmay adhere to the two wires or which will be drawn down to such a finefilament as to be broken by the whipping action and in either case willdrop downwardly after it has become substantially completelyset due toloss of volatile solvent therefrom. 40

When it is merely desirable to gather a fiufied. mass of fibers it isonly necessary to position a containing means such as the box 28 beneaththe wires so that the fibers may drop down therein and be collected inthis manner.

When it is desired to produce a fiber having a considerable crimp orcurl, it is found desirable to impart a high potential alternatingcurrent to the two wires l9 and 20 so that each of the wires willalternately become positively and negatively charged in accordance withthe period of the cycle of the alternating current. By operating in thismanner, it is found that the stream of solution which is gradually beingfed in the form of a fine fiber will not only be whipped between the twowires I9 and 20 but will also be drawn back and forth in accordance withthe period of the cycle of the alternating current so as to form smallfolds or crimps therein. This is illustrated by the fibers formed fromnozzles l1 and I8 in Figure 1 of the drawings. Nozzles l5 and IS inFigure 1 of the drawings illustrate the path of the spinning solutionstream and resulting fibers when one of the electrode wires isconstantly charged with one charge of electricity and the otherelectrode wire is given a constant charge of opposite polarity.

Referring to Figure 2 of the drawings, the conducting wires 3| and 32are arranged vertically instead of horizontally as illustrated in Figure1.

In this case, the wires 3| and 32 are also preferably arranged in aconverging relationship from the upper supports 33 and 35 to the lowersupports 31 and 39. When the conducting wires are arranged in thismanner, it is found that the fine fibers formed will more readilyseparate from the wires and drop to they collecting belt 4| which movesslowly in the direction of the arrow and permits the building up of asliver 43 which can be easily collected on a slowly rotating bobbin orthe like.

In the modification shown in Figure'3 of the drawings, the conductingelectrode wires 41 and 44 are positioned substantially horizontally andare positioned in a converging relationship to each other from thesupport 5| to the support 53. It'has been found that when the two wires41 and 44 are positioned in a converging relationship, as abovedescribed, the fibers will adhere thereto and automatically travel inthe direction of the convergence of the wires as shown by the arrow inFigure 3. The fibers will collect adjacent to the support 53 and as thefibers become substantially completely set due to the evaporation ofvolatile solvent will drop downwardly onto the belt 55 where the fibersare collected in the form of a sliver 57 which can be slowly wound ontothe bobbin 59.

Referring to the embodiment of the invention shown in Figure 4, theconductor electrode wires ceptacle H through the header conduit l3 andextruded from a substantially horizontal row of nozzles. Thehorizontally positioned wires are vertically spaced from each other andare stretched between vertical insulating supports 65 and 61. Thenozzles in this case must be spaced somewhat above a line bisecting thespace between the wires so that the stream of spinning solution willcome within the zone of influence of the electrical fields surroundingthe wires after flowing downwardly a distance from said nozzles. Thestream of spinning solution will be whipped up and down due to thealternate attraction and repulsion. The solvent evaporates from thespinning solution as it is whipped up and down resulting in theformation of fine fibers between the electrode wires. A collecting wheel3 69 is positioned between the wires as shown in streams of solutionbetween the wires.

ferred that the current of air be heated so that the fibers formed inthe process will be more quickly dried.

' In all of the modifications as shown in the accompanying drawings andas described above, the spinning jets are electrically neutral, that isto say they bear no charge of electricity. In view of the fact thatthese spinning jets or nozzles may become electrically charged from oneof the conducting wires by travel of the current along the stream ofspinning solution, it may be desired to ground the conduits l3 by meansof a wire 2| as illustrated in Figure l or wire 13 as shown in Figure 4.

In the preferred embodiment of the invention the spinning solution isextruded from a grounded, neutral spinning jet spaced from the planewithin which the electrode wires lie and positioned between the twocharged electrode wires so that the oppositely charged electrical fieldscause the at least partially set filament to whip rapidly back and.forth between the two electrode wires. This preferred position of thenozzle varies with factors such as the temperature and humidity of thesurrounding atmosphere, the concentration of the spinning solution, theelectrical potential charged on the two conductors, etc. With suchfactors substantially constant and with an electrical potential chargeof 30,000 to 100,000 volts or more on the conductors, the spinning jetis positioned preferably a distance of at least 12 inches from the planewherein the two conductors lie. Preferably, the conductors are chargedwith a high potential, alternating current so thata decided curl isimparted to the resulting filaments or fibers as they are folded backand forth between the conductors. The mass of folded filaments andfibers is collected and associated into a bundle or sliver by anysuitable collecting means. The collection of the mass of foldedfilaments and/or fibers from the two conductors may be carried out insuch a. manner as to break or tear the same into smaller staple lengths.

Without wishing to be limited thereto, the following examples will begiven as illustrative of the present invention.

Example I A spinning jet having an orifice diameter of 0.0180 inch isplaced at a distance of approximately l236 inches from the plane whereinlie two vertically extending conductor wires and is positionedapproximately on a perpendicular bisector of the said plane. The twowires are charged oppositely to each other by connection to oppositepoles of a source of pulsating direct current of 30,000 to 100,000volts, or more. From the grounded and neutral spinneret a solutionconsisting of 150 grams of cellulose acetate, 600 grams of acetone and300 grams of the monomethyl ether of ethylene glycol is extruded in theform of a filament towards the charged wires. The filament appears toproceed along a curved path until the solvents have partially evaporatedand then begins to whip to and fro with increasing intensity andrapidityas the filament enters and reaches the electrical fields of the twowires. This whip action is apparently engendered by virtue of each ofthe two wires attracting the filament to its proximity until thefilament acquires a charge of like sign, whereupon the wire repels thefilament back to the oppositely charged wire which exerts an attractiveforce on the filament. The filament is thus folded alternately back andforth between the two wires and in doing so, is broken to a certainextent into fibers of varying lengths. Upon continued spinning, a massof fibers builds up and vibrates between the two wires until shrinkagefrom the drying separates the fibers from the wires and the mass dropsby virtue of gravity to the floor. The resulting fibers are lustrous andsomewhat curly and have a pleasing hand and a relatively good tenacity.Instead of fiufled staple, the product may be collected substantially asa continuous bundle or sliver of fibers by means of a moving belt orwheel suitably positioned between the two wires.

Example II The procedure of Example I is followed except that the twowires are charged oppositely to each other by connection to oppositepoles of a source of 60 cycle, alternating current of 30,000 to 100,000volts, or more. In whipping back and forth and in subsequent vibrationbetween the wires, the fibers surprisingly acquire a crinklecorresponding roughly in form and intensity to the sine waves and nodesof the alternating current. The crinkle, of course, is modified slightlyas the fibers dry and separate from the wires. Except for the moredecided crinkle, the fibers are essentially the same as those secured inExample I. The fibers may be collected as a fiufled staple, or may becollected as a substantially continuous bundle or sliver of fibers bymeans of a moving belt or wheel suitably positioned adjacent the twowires.

- Example III The same arrangement and procedure are repeated as inExample 1, except for the following points. The two oppositely chargedconductors extend horizontally and are positioned parallel to each otherin a vertical plane. To offset the effect of gravity and to secure theoptimum whipping action of the filament between the two conductors, thespinning jet is placed above the perpendicular bisector of the planewherein the two conductors lie. The fibers are collected continuously ona rotating wheel rim projecting through the plane wherein the twoconductors lie and positioned approximately at the electrical midpointbetween the two conductors. Collection of the fibers on the rim of thewheel tears the fibers into shorter staple lengths. From the rim of thewheel the fibers are taken ofi in the form of a continuous bundle orsliver by the rubbing action of a leather belt arrangement which movesslowly around the wheel rim and carries the sliver upward into a guidearm from which the sliver is wound into a skein upon a suitable rotatingsupport.

Moreover, the two conductors do not have to be parallel. Instead, thetwo conductors may be gradually and slightly converged towards eachother in such a fashion as to compensate for the progressive shrinkageof the fibers as they dry. This arrangement is particularly advantageousin the production of flufied, crinkled staple by connection of theconductors to a source of high potential, alternating current. Theimposition of the crinkle, patterned substantially after the sine wavesof the alternating current, is apparently facilitated by the fibersbeing kept under more severe vibration during their drying period.

In the above examples, for the most part, electrically charged wires ofcopper or the like have served as conductors or electrodes.v It will, ofcourse, be evident that the wire conductors may with equal advantage bereplaced with strips, sheets, shields, plates or the like made of anyelectrically conducting substance such as copper, silver, iron, etc.

The distance between the oppositely charged conductors should exceed thedistance at which sparks would be engendered between them and should besumciently small so that the partially set filament is alternatelyattracted and repelled by the electrical field of each conductor.

Barring the effect of gravity as in the case wherein the conductorsextend horizontally and lie parallel to each other in a vertical plane,the neutral spinning means is preferably, as in the above examples,positioned in the extension of a plane coinciding with the neutral zoneexisting between the electrical fields of the oppositely chargedconductors. Consequently, the position of the spinning means is adjustedwith factors which influence the location of the neutral zone which mayor may not be neutral with respect to the ground. Such factors are theelectrical potential on each conductor, the size and shape of theconductor, the material from which the conductor is made, etc.

As cited in the above examples, the product of the invention may becollected as fiufled staple, or as a continuous bundle or sliver offibers. If a fiufied staple is desired the fibers are simply allowed tofall by gravity to the floor or into a container and the accumulatedmass of fibers is removed by suction, by a stream of gas or fluid, or bya belt or other mechanical means. The fluifed staple fibers may beconverted as desired into a slivers by the usual textile operations. Ifthe direct production of a continuous bundle or sliver of fibers isdesired, the fibers as they vibrate between the conductors aremechanically collected on a grounded endless belt or the rim of a wheelor the like. The collecting means is shaped to best adapt it to the pathit is to travel and its position with respect to the conductors asheretofore described in the examples.

A current of air or the like may be blown on the filaments issuing fromthe spinning nozzle to assist in directing the filaments to theconductors and also in promoting a more rapid evaporation of solventtherefrom.

The present invention may also be applied advantageously to the spinningof solutions of cellulose acetate in solvents other than acetone or themonomethyl ether of ethylene glycol. Likewise, solutions of othercellulose esters, for instance cellulose propionate, celluloseacetopropionate, cellulose acetobutyrate, cellulose acetostearate andsolutions of cellulose ethers, such as ethyl or benzyl cellulose mayalso be spun by the procedure of the invention. Generally, solutions ofresins such as polymerized alkyl esters of acrylic- It has also beenfound that the addition of electrolytes such as salts, acids or baseswhich affect the conductivity of the spinning solution may be added toadvantage in causing the fibers to oscillate more energetically, therebyproducing more curl in the resulting fibers.

In the present invention the fibers are not formed by precipitation orcoagulation induced by electrical means. Rather, the solvent ispreferably permitted to evaporate to some extent from the filament in anormal manner so that the filament is in a partially set conditionb'ei'ore it is subjected to the whipping action between the conductorswhich breaks the filament into fiber lengths to a certain extent. As theresult of this technique, a fiber of good hand and of relatively goodtenacity is secured. In the apparatus of the invention the grounded andneutral spinning jets facilitate continuous spinning since fibers do nottend to gather or form on the jets so much as in other electricalmethods of spinning. Moreover, since there is no electrical charge onthe jet, any fibers accidentally adhering to the spinning jet may bereadily and promptly removed without interrupting spinning. The fibersof the invention, of course, find valuable application in making fabricstherefrom either alone or mixed with cotton or wool. In wool mixtures,the fibers made in accordance with the invention by the use of analternating current are particularly adaptable since they possess adecided curl and have a handle which corresponds quite closely to thatof wool.

It will be obvious that many changes and modifications can be made inthe above described apparatus and processes without departure from thenature and spirit of the invention. It is therefore to be understoodthat the'invention is not to be limited except as set forth in theappended claims.

I claim:

1. A method for the production of artificial fibers which comprisesextruding a stream of spinning solution from a neutral spinning jet intoa neutral atmosphere a substantial distance to become partially set,then passing the same between spaced, high potential electricallycharged electrodes of opposite polarity in which the polarity isperiodically alternated, thereby whipping said streamof spinningsolution alternately in opposite directions to cause the same to bedrawn out into fine fibers and then collecting said fibers in the formof a sliver.

2.,A method according to claim 1 in which the electrodes are positionedsubstantially horizontally and in a converging relationship, the fiberstraveling in the direction of the convergence of the electrodes.

ANTON FORMHAIS.

